Martine Kimberley Sherrie Ponting was born on 14 May 1976 at the Salvation Army Mothers' Hospital in the London Borough of Hackney to Jenny Ponting and Thomas "Keith" Hemmings. While in a relationship with Keith, Jenny experienced domestic violence, which continued for many years after their split. After one of many incidents in which he attempted to kill both Jenny and Martine, he was arrested and later charged and remanded in custody for six months. Jenny then met John McCutcheon, whom she later married. When Martine was nine, Keith contacted Jenny and asked for access to her. Jenny refused prompting him to seek sole custody of Martine through the courts. He eventually lost the case, was denied any access to Martine until she was 18, and told that he could not apply for it again due to his past behavior. Shortly after, her surname was changed to her stepfather's, McCutcheon. When Martine was sixteen, her mother gave birth to her half-brother, Laurence "LJ". Jenny and John eventually divorced, and she married Alan Tomlin in 2000.
At the age of 12, McCutcheon obtained her first acting role and was paid £350 to appear in an American television commercial for the drink Kool-Aid, which was followed by modelling assignments and bit parts in TV shows. She was given the part of Mandy in the TV series Bluebirds (1989) alongside Barbara Windsor, and played Susan, Jane's sister (played by Denise van Outen), in the Anthony Newly directed production of Stop the World – I Want to Get Off, at the Churchill Theatre in Bromley, London, later transferred to the West End Lyric Theatre in Shaftesbury Avenue. This was followed by two guest appearances on the ITV police drama The Bill in 1991 and 1992. McCutcheon also appeared in the music video for the song "Caribbean Blue" by Irish singer Enya. By the time she was 15, she was part of an all-girl group, Milan, with two fellow pupils, and landed a record contract with Polydor and a gig touring as the warm-up act for the British boyband, East 17. Milan were reasonably successful. Three of their singles: "Is It Love You're After", "Affectionately Mine" and "Lead Me On", charted in the top ten of the dance charts, with the latter also making it to the top 100 of the UK Singles Chart. However, they were not successful enough to make a living and disbanded.
In 1994, McCutcheon was offered the small part of Tiffany Raymond on the popular BBC soap opera EastEnders. The role of Tiffany grew as did McCutcheon's popularity and 22 million viewers tuned in to see her final scenes in Albert Square in 1998 when her character was killed off in a special episode screened on New Years Eve. In reality, McCutcheon had decided to leave the soap in order to embark on a pop career and the death of her character was not viewed favourably by the Actress as she had intended to return. Since leaving the show, McCutcheon has publicly slammed the BBC's "Controller of Continuing Drama Series", Mal Young, who made the decision to kill her character. She accused him of treating her unfairly and bringing her role in the soap to an end so irrevocably, merely as punishment for leaving. In turn, Young has hit back at McCutcheon, saying her anger only arose because she wanted him to keep her role in EastEnders open as a "safety net", in case her pop career failed, and he was not prepared to do this.
McCutcheon's first appearance on the charts occurred in 1995 on a minor dance song "Are You Man Enough" with the dance producers Uno Clio. A promotional video was also produced. In 1999, she debuted as a solo pop Artist with Virgin Records and scored a number one on the UK Singles Chart with the ballad "Perfect Moment" (originally recorded by Edyta Górniak in 1997). Also that year, she had two more top 10 entries, reaching number six with two singles: "I've Got You" and later with "Talking in Your Sleep", which featured the double A-side "Love Me", an album track that was re-recorded for the Children in Need appeal with all proceeds being donated to that cause. The three singles were taken from her debut album, You Me & Us, which peaked at number two on the UK Albums Chart and was certified platinum by the British Phonographic Industry (BPI).
McCutcheon's debut studio album You Me & Us (1999) peaked at No. 2 in the UK, was certified platinum and spawned the UK No. 1 single "Perfect Moment" and two other top 10 hits. Her second studio album, Wishing (2000), was less successful, peaking at No. 25. However, it produced two top 10 singles and was certified gold. Her pop career stalled because of the poor reception of her third album, Musicality in 2002, which only reached No. 55 in the UK and received silver certification. She has since appeared on various television programmes, in films and on stage in My Fair Lady, where her portrayal of Eliza Doolittle won her a Laurence Olivier Award in 2002. She released her autobiography Who Does She Think She Is? in 2000. In 2017, she returned to music with the album Lost and Found, which peaked at No. 17 in the UK, becoming her highest-charting album since her debut.
McCutcheon released her autobiography, Who Does She Think She Is? in 2000, and in 2003 Martine McCutcheon: Behind the Scenes – A Personal Diary, was published by HarperCollins. McCutcheon was one of many celebrities who featured in a 2004 promotional film for London's successful bid for the 2012 Summer Olympics. A fitness DVD, Martine McCutcheon: Dance Body, was released in December 2005.
In 2002, McCutcheon presented the National Music Awards for ITV1 and in 2003 she featured in her only major film role. She appeared as tea-lady Natalie in the Richard Curtis romantic comedy Love Actually, where the British Prime Minister (played by Hugh Grant) falls in love with McCutcheon's character. The film received good reviews and was a box office success. McCutcheon went to America in the wake of the film's success, but a Hollywood career did not materialise. However, she did win the MTV Movie Award for Best Trans-Atlantic Breakthrough Performer. She also won the Empire Award for Best Newcomer at the 9th Empire Awards 2004 ceremony.
In September 2005, she appeared in two episodes of BBC drama series Spooks. Screened on the UK television network ITV1 in December 2005, McCutcheon appeared in The English Harem, playing a woman in love with a Muslim man (Art Malik), who marries him, despite knowing he already has two wives. That same year she presented and performed on ITV's entertainment programme, Moviemusic Mania. In 2007, McCutcheon was seen in two independent films, Withdrawal and Jump!, as well as the Agatha Christie's Marple television series episode "At Bertram's Hotel". She was also a judge for the second series of ITV1's Soapstar Superstar. Her appearance on the show drew criticism, with reports alleging that she was becoming a hate figure for the contestants, who were said to have found her comments relentlessly critical and at times patronising. She performed in an Art Plus fundraising event at the Whitechapel Art Gallery opposite Natalie Press, Samantha Morton and Rhys Ifans, and in January 2008 she featured in the ITV soap Echo Beach as the character Susan Penwarden.
In 2006, the supermarket chain, Tesco, announced that they would be using McCutcheon in a series of adverts to promote a new green scheme for recycling used plastic carrier bags. In 2009, her first novel, The Mistress, was published by Pan MacMillan. From 2010 until 2011, she was the face on Danone's UK advertising campaign for its Activia yogurt brand.
In 2013, she was declared bankrupt by the Kingston upon Thames County Court with creditors including HM Revenue and Customs.
In July 2014, she was awarded an Honorary Degree by the University of Bolton for her services to entertainment.
McCutcheon was engaged to DJ Gareth Cooke, but broke off the relationship in 1996. She was also in a relationship with Jonathan Barnham, with whom she fell pregnant in 1999, however she miscarried. McCutcheon married singer Jack McManus at Lake Como in September 2012. The couple had been dating since 2009. On 4 February 2015, she gave birth to a son, Rafferty Jack McManus.
In September 2016, McCutcheon was announced as a regular panellist on the ITV daytime show Loose Women, after making a few guest appearances on the show earlier in the year. She left the show in 2017 after one season.
McCutcheon returned to music in 2017 with her fourth studio album, Lost and Found, released in August by BMG. Its lead single, "Say I'm Not Alone" was released on 30 May 2017. The album peaked at number 17 in the UK, becoming McCutcheon's highest-charting album since the release of You Me & Us.